This invention relates to apparatus for controlling the direction of vehicular traffic flow so as to inhibit wrong way traffic or motor vehicles at designated locations.
The control of traffic flow in particular areas is necessary to ensure continuous traffic movement and to prevent unauthorized use of certain rights of way. At present, it is common to use a visual warning coupled with a road-mounted barrier that is routinely deflected by the wheels of a motor vehicle when the vehicle is traveling in the permitted direction. Typically, this is brought about by the use of rotationally mounted levers extending upwardly from beneath the road surface. When a vehicle tire contacts one or more of the levers, they are readily moved to a position below the road surface so as to permit authorized traffic flow.
In the case of traffic flow in the unauthorized direction, the device customarily contains tire damaging means which are preferably actuated by the vehicle tire rather than being motor driven. The tire damage leaves a lasting impression, not only on the driver of the vehicle moving in the non-permitted direction, but also on passengers, onlookers and the community at large. Thus, observation of effective operation and word of mouth play major roles in the device's effectiveness. The efficacy of devices of this type rely on the piercing of or shredding of a vehicle tire that has entered the designated area and then attempts to move through or across it contrary to the warning signs. The vehicle tire contacts the lever causing a normally retracted or hidden damage mechanism to appear and produce its designed-for effect. To the extent that vehicular traffic can be carried out in the non-permitted direction without causing damage, the device not only fails on this particular occasion, but also fails to provide the desired notice to the community that undesirable consequences will occur if the signage and other traffic flow indicators are not obeyed.
One traffic flow regulating device is disclosed in U.S. Pat. No. 4,158,514 wherein each upwardly extending lever is made integral with a barrier blade. The blade assumes a normally retracted position below the surface. When the tire of a vehicle traveling in the non-permitted direction engages the free end of an upwardly extending lever arm, it is expected that the lever will be depressed in the direction of the traffic flow and urge the associated blade up against the tire so as to produce a shredding effect. In the permitted direction, the levers are contacted by the tire and the blades are rotated in the opposing direction so that they never appear above surface and do not constitute a hazard during normal use. The device is preferably constructed so that the axis of the lever and that of the associated blade form an angle of the order of 90 degrees that the blade does not emerge accidentally during traffic movement in the permitted direction.
While this device may be effective in the case of solid vehicle tires or highly pressurized tires, the present day passenger vehicle is usually provided with relatively low pressure tires characterized by a wide tread. Consequently, it has been found that many tires in general use tend to frictionally engage and envelop the free end of the lever. As a result, the tire surrounds the adjacent portion of the lever and urges it backward in the direction of rotation of the tire. This direction is contrary to the direction of movement of the vehicle and corresponds to the permitted direction of traffic flow across the apparatus. The frequent result is that the device does not operate as intended and no damage to the vehicle tire takes place.
Accordingly, the present invention is directed to the provision of a vehicular traffic controller wherein the tendency of the vehicle tire to frictionally engage or envelop the lever arms is substantially eliminated. The ability to inhibit this envelopment results in increased operating reliability in that the spike associated with each lever arm is able to emerge from its retracted position and engage the tire. Thus, the present invention is constructed to produce the desired result of tire damage when the device is traversed by a vehicle moving in the non-permitted direction.